Various conditions are treated by implantation of a medical device secured by a screw, the screw being installed using a screwdriver having a powered rotating shaft.
As an example, urinary incontinence is a condition that occurs in men and women, and that can be treated by installation of a medical implant. In women, urinary incontinence may be caused by urethral hypermobility, a condition in which the bladder neck and proximal urethra may rotate and descend in response to increases in intra-abdominal pressure. Hypermobility can result because of aging, child delivery, or conditions that weaken, stretch, or tear the muscles around the bladder, bladder neck, urethra, or a combination of these. Urinary incontinence can also be caused by intrinsic sphincter deficiency, a condition in which the urethral sphincter does not coapt properly. In males, urinary incontinence may be caused by damage to the urethral sphincter such as can occur after prostatectomy, after radiation treatment, or after pelvic accidents. Other reasons for male incontinence include bladder instability, over-flowing incontinence, and fistulas.
There are numerous approaches for treating urinary incontinence. In a bladder neck suspension procedure for treating hypermobility, sutures are placed around the muscle groups on either side of the urethra and are affixed to the pubic bone or other supporting structures to reposition and resuspend the proximal urethra. Also common are sling type operations, which may be performed to treat urethral hypermobility, intrinsic sphincter deficiency, or both. In a sling type operation, a sling is placed under the urethra and bladder and is tensioned to elevate and stabilize the urethra, prevent excessive downward mobility, or compress the sphincter to treat intrinsic sphincter deficiency.
In these procedures, sutures are anchored to supporting structures such as the pubic bone, Cooper's ligament, or the rectus fascia. Bone anchor placement devices are often used to place bone anchors at selected insertion sites in the pubic bone. Sutures can then be attached to the bone anchors.
One type of bone anchor placement device suitable for installing a bone anchor in the pubic bone is a medical screwdriver. One known medical screwdriver is disclosed in U.S. Pat. No. 6,602,260 to Harari et al. The medical screwdriver of Harari et al. includes a body and a drive shaft that has an end that can drive a bone screw. A sleeve or sheath can be used to isolate the drive shaft from surrounding tissue. The sleeve is stationary and prevents the rotating shaft from injuring tissue surrounding a bone into which a screw is inserted. The sleeve includes a key that fits in a notch in the body of the screwdriver. In use, a surgeon connects the sleeve to the body of the screwdriver by aligning the key of the sleeve to the notch in the body of the screwdriver.